Symptoms
Issue #1: Workflow deployment is failing with this error message
'An item with the same key has already been added'
Issue #2: Receiving a 'Validation Details' error when trying to create package
Error: SmartForms Integration Form_name' is referencing the Missing ID Unknown that could not be found
Diagnoses
K2 artifacts are not in-synced with the SharePoint list.
Resolution
Check out each form, then immediately check it back will re-sync the form definition. This allows us to deploy the workflow. The next step is that we will need to run through the Workflow Settings (Start) wizard and also all of our SmartForms client event wizards in this workflow and redeploy the workflow. Finally, the K2 package can be created without an issue.